1. Field of the Invention
The subject invention relates to an assembly for blowing liquids from the surface of a vehicle in a car wash.
2. Description of the Related Art
Assemblies for blowing liquids from a vehicle are well known and typically include a plenum for distributing air to a plurality of nozzles that direct air from the plenum toward a vehicle. The plenum is supplied air by a blower system having an inlet for sucking air in and an outlet for supplying pressurized air to the plenum for distribution to the nozzles. Such blowers include an impeller that is rotated in a housing by an electric motor, the impeller acting as a pump or compressor to pressurize air and force it into the plenum system.
There are significant periods during the operation of a car wash that there is no demand for blowing liquid from a vehicle, i.e., periods without a vehicle passing through the car wash. It is generally very detrimental to an electric motor to start and stop the motor. It is much more efficient in electrical power usage and maintenance of the electric motor to run the motor continuously. This problem has been approached by controlling the delivery of pressurized air from the blower impeller by controlling the flow of pressurized air in the outlet from the impeller, as disclosed in U.S. Pat. No. 4,836,467 to Rodgers. However, during the idle periods of no demand, the motor and impeller remain under load, and sometimes an increased load because of backpressure.